Changes in cognitive characteristics according to 3 intensity changes by 8 vibration frequencies (STROBE)

Abstract

In this study, we attempted to observe changes in cognitive characteristics according to 3 intensity changes (Level 1: 0.25 gravity, Level 2: 0.38 gravity, Level 3: 1.3 gravity) at 8 vibration frequencies (10, 50, 100, 150, 200, 225, 250, 300 Hz). The subjects were twelve male (22.1 ± 0.6 years old) and twelve female (21.5 ± 0.8 years old) healthy, right-handed adults with normal cognitive abilities. An experimental trial consisted of a stimulation phase (0.1 sec) in which a vibration stimulus was presented and a rest phase (6 sec) in which no vibration stimulus was presented. A selected stimulus was presented on the first knuckle of the right index finger 5 times (trials). Cognitive characteristics scores according to changes in intensity at each frequency were sampled using a subjective assessment sheet consisting of eighteen items (“ticklish,” “shivery,” “push,” “convex,” “thick,” “numb,” “slow,” “fast,” “shallow,” “strike,” “weak,” “strong,” “dense,” “blunt,” “heavy,” “light,” “stab”, “no stimulus”). To identify the cognitive characteristics according to intensity changes by frequency, the 3 intensities were designated as variables, and a curve estimation regression analysis was performed. At 10 Hz, cognitive characteristics of ’blunt’ increased with the intensity, and ’weak’ decreased. In 100 and 225 Hz, increase or decrease in intensity led to opposite cognitive characteristics (‘weak-strong’ in 100 and 225 Hz, ‘light-heavy’ in 225 Hz). In 100 and 225 Hz, as the intensity increased, expressions on the sense of surface such as ’blunt’ were superior, and the shape of an object (thick) and dynamics (push) differed with the change in intensity. In addition, in 225 Hz, decrease in intensity led to increase in cognitive characteristics such as ’light’ and 'shallow. ’Fast’ was unique in that it only appeared as the intensity increased at 300 Hz.

Study on the Cognitive Characteristics Induced by Changes in the Intensity, Frequency, and Duration of Vibratory Stimuli

“…In previous studies, as the intensity increased at 225 Hz and 250 Hz, the intrinsic property of vibrational stimulation, 'vibrating', became dominant 5 . In this study, the cognitive trait was induced not only by the high intensity but also by increasing the stimulation duration.…”

“…In our previous studies [3][4][5] , we performed a systematic experiment to understand the changes in cognitive characteristics according to the changes in the various parameters of vibration stimulation. First, the cognitive characteristics under each of the nine frequencies (10, 50, 100, 150, 200, 225, 250, 275, and 300 Hz) were extracted at a xed intensity 3 .…”

“…Moreover, based on intensity, the characteristics 'fast', 'shallow', and 'light' appeared in the high-frequency vibration stimulation band of 200-300 Hz. Third, to extract the cognitive characteristics according to the intensity change for each of the eight vibration frequencies, three intensities were designated as variables and a curve estimation analysis regression analysis was performed 5 . At 100 Hz and 225 Hz, as the intensity increased, the cognitive characteristic scores of 'strong' and 'heavy' increased, and the cognitive characteristic scores of 'weak' and 'light' decreased.…”

“…A questionnaire was prepared to analyze the changes in cognitive characteristics according to intensity, frequency, and stimulation duration. Responses related to tactile, temperature, pain and kinesthetic senses were collected based on the subjective evaluation questionnaire used in our previous study [3][4][5] . In addition, the meaning of each word was examined using the standard Korean dictionary published by the National Institute of the Korean Language (http://stdweb2.korean.go.kr/).…”

“…A majority of the studies focus on the frequency and intensity of a vibrating stimulus 2 because they have a signi cant effect on a user's perception of touch. In our previous study, to identify the cognitive characteristics of a vibration stimulus under various variables, we investigated stimuli under various frequencies and intensities and analyzed and reported the cognitive characteristics evoked under the stimuli [3][4][5] . However, a study on the cognitive characteristics that can appear under a combination of variables other than frequency and intensity has not yet been conducted.…”